Service Level Agreement Monitor (SALMon)

One of the most successful architectural styles nowadays is service oriented architecture (SOA). In this type of architecture there are a lot of dependencies between services, but each service is an independent element of the system. In this situation we need some way to ensure that every service is working correctly and to take actions when something goes wrong to evolve the architecture as fast as we can. For example, if one of the lower level services of the service composition stops working, it could lead to a total or partial system malfunction. In this situation there is a need to be able to build reliable SOA systems. Our proposal, SALMon, is based on monitoring the services for service level agreement (SLA) violations. The SALMon architecture is composed of three types of components: Monitors that are composed of measure instruments, the measured quality attributes being taken from an ISO/IEC 9126-1-based service oriented quality model; analyzers that check the SLA rules; and decision makers that perform corrective actions to satisfy SLA rules again. These 3 types of components are mostly technology-independent and they act as services inside of a SOA system making our architecture very scalable and comfortable for its purpose.